The availability of over 45,000 accurately surveyed ground points covering an area of 1,000 km2 in central Eritrea
has enabled comprehensive accuracy assessments of elevation mapping from IKONOS, GeoEye-1, WorldView-1
and WorldView-2 stereo satellite photos. The ground survey points were acquired for a base metal mining
exploration gravity survey. All of the ground points were surveyed with Real Time Kinematic GPS instruments and
are accurate to 2 cm. The IKONOS, GeoEye-1 and WorldView-1 stereo photos were each registered to a single
ground control point, and the WorldView-2 stereo photos were registered to two ground control points. Each of the
stereo pairs covers a slightly different ground area.